In both-sided printing performed by a conventional printer, a system supplies the same printing data as in one-sided printing to the printer. Accordingly, odd-numbered pages in one-sided printing are printed on the front sides of printing paper sheets, and even-numbered pages are printed on their back sides.
In the case of a document having a cover, the first page of the text, subsequent to the cover sometimes needs to be started as the first page after the cover, not from the back side of the cover. In conventional both-sided printing, however, odd-numbered pages in one-sided printing are printed on the front sides of paper sheets, and even-numbered pages are printed on their back sides. Consequently, the first page following the cover is always the back side of the cover. Also, when an elaborately designed document such as an album is to be printed, if the total number of pages of the document is an odd number, the back side of the last page becomes white (=solid). This makes the document inappropriate in design.